It's estimated as many as one in four Americans will experience an anxiety disorder some time in their lives. An economic analysis suggests anxiety disorders cost 42 billion annually in terms of lost workplace productivity, absenteeism and medical and pshychological care. Dr. Peter Norton is an assistant professor of psychology at the University of Houston. He says everyone feels some sort of anxiety in certain situations, but that doesn't mean you have a disorder.

"What an anxiety disorder is, is where that whole anxiety or fear system goes off in the absence of any real danger or any objective danger, or goes off a lot more than it should given the amount of danger."

Anxiety disorders can include panic attacks, social anxiety, obsessive compulsive disorder, post-traumatic stress disorder and phobias. People who have true anxiety disorders usually find them disruptive to normal life. Norton says anxiety disorders are chemically similar to depressive disorders. Both are partly caused by seratonin levels.

"But we also know with both anxiety and depression, the various life events can have a strong impact. So if I had, if I grew up in a household where my parents were always saying 'you need to make a good impression, you need to be popular or else nobody will like you' I might be more susceptible to develop a social anxiety."

Norton and his graduate students run an anxiety clinic on campus, where they accept patients for group cognitive behavioral therapy. This allows the students to get real experience and training in a clinical setting. Norton says he thinks his students are already better at working with anxiety disorders than a number of professionals in private practice.

"Also, being situation on the UH campus, uh puts us in some fairly low income neighborhoods, um and also it puts us near, uh nearby some very ethnically diverse neighborhoods. Um, so that really allows us to reach out to a number of different communities that traditionally have been underserved."

Sessions are $20 for the public and $10 for UH students. Norton says he and his students treat between 10 and 20 patients per session. Depending on the severity of the anxiety disorder, therapy could continue for a few weeks to several months.